Relationship between Vitamin D status and skin colour, season, cognition and depressive symptoms. (a) Influence of skin colour and season on serum vitamin D concentrations; (b, c) influence of vitamin D status on (b) cognition assessed by ACE‐R scores and (c) depressive symptoms assessed by BDI‐II; and (d) correlation between serum vitamin D concentrations and ACE‐R score. Statistical results from (a) two‐way anova including skin colour and ethnicity as between‐subject factors, indicating a significant effect of skin colour and season but no interaction effect (n = 353); (b, c) one‐way ancova including vitamin D status group as between‐subject factor, correcting for age, gender, time since TBI and PTA duration >1 week, *P < 0·05, **P < 0·01 (b: n = 27 replete, n = 66 insufficient, n = 77 deficient; c: n = 53 replete, n = 95 insufficient, n = 123 deficient); (d) r
s indicates Spearman's correlation coefficient, n = 175. Abbreviations: ACE‐R, Addenbrooke's Cognitive Examination‐Revised, BDI‐II, Beck Depression Inventory‐II; PTA, post‐traumatic amnesia; TBI, traumatic brain injury. To convert vitamin D concentrations from nmol/l to ng/ml divide by 2·496.